The present invention relates to the field of power supply of electrical equipment by a renewable energy source and an energy storage element.
It relates in particular to equipment such as a solar LED lighting system comprising a LED lighting module, a photovoltaic panel, a power battery and an electronic circuit for managing energy.
The invention is however not limited to lighting, and also applies to other equipment powered by a renewable energy source and incorporating a storage means.
Solutions for optimizing the operation of such equipment are known in the state of the art.
For example, French Patent FR2922628 discloses a lamp comprising a pole fixed in the ground, a lantern fixed to a free end of the pole and comprising a lighting device and a power supply block adapted to supply electrical power to the lighting device. The power supply block comprises an electrical accumulation battery, an assembly of photovoltaic cells, a wind turbine, and an electrical accumulation circuit provided for charging an electrical accumulation battery from the electrical power provided by an assembly of photovoltaic cells and a wind turbine.
U.S. Pat. No. 5,151,865 discloses a method for determining the energy content value (EIW) of a battery by measuring the terminal voltage (UKL) of an energy store, while taking into account at least one reference value (BW), that is formed from a sum current (IE) flowing in the energy store in a specific time unit (dt) and in a specific operating voltage range (BSB). This reference value (BW) thus represents a function value. The measured terminal voltage (UKL) referred to the function value (FW) corresponds to a specific energy content value (EIW) in the energy content range (EIB).
U.S. Pat. No. 6,081,104 discloses a system for delivering power to a battery and to a load. The battery can be charged by the power source and used to supply energy or power to the load when the power source is unable to provide sufficient energy and power to the load. The system reduces injection of DC current into the load and, as a result, extends the operation life of the load, particularly if the load is a lighting system. The purpose of this system is to prevent premature ageing of the lighting load or of the battery.
U.S. Pat. No. 6,191,568 describes a load voltage modulation solution and power control and supply system for the supply of power to a load for which, over particular periods of time, usually on a daily basis, it is desired to reduce power. The invention has particular application to street lighting systems in which, for a period of several hours during the night (when traffic is minimal and many people are asleep), the luminaires of the lighting system can operate at reduced power.
The international patent application WO2011/095922 describes a method for controlling the light output profile on the basis of the lighting demand and the battery capacity under consideration of keeping the energy storage level above a predetermined minimum level during a predetermined time period, consisting in taking into account weather forecast data periodically acquired via an internet connection.
The main drawback of the solutions proposed in the prior art is that the guarantee of continuity of operation requires the oversizing of the power storage element and also of the renewable energy source since the system consumption is not adapted to the available energy of said energy storage element.
Failing that, if the storage element is not oversized, the special conditions encountered during certain operating cycles lead to an untimely interruption of the service provided by the electrical equipment.
Furthermore, the solution implementing the periodical acquisition of weather forecast data requires a connection to a future data server, and access to relevant predictive models with respect to the location of the lighting system.
Such forecast data are usually macroscopic, even extrapolated, and cover much greater areas than the implantation area of a lighting system.
The solutions of the prior art such as the one disclosed in WO2011/095922, indeed provide a response to the aimed continuity of service (“no blackout”), but require access to a data infrastructure such as a weather data base acquired by a server, preventing the implementation in areas underserviced by radio-frequency applications. Furthermore, these solutions require energy-consuming radio communication means, which goes against the objective of optimizing consumption and maximizing the service continuity using “frugal” means for generating and storing energy.